Help with Bi-directional serial comminucation with an arduino(uno, for example) device.


I have a working sketch for my arduino device that outputs serial data. I’ve tried following the following as a basis for getting started, but had no luck:

My goal is to be able to send/recieve data to/from my BBB. Can anyone provide some insight, based on their personal experience and success, on how to get this accomplished. The device tree modifications seem to be successful, but I’m still having a hard time getting this thing going. Also, does it make a difference weather or not the BBB is powered by usb or 5v outlet?

Need more information. What is your exact problem ? What are the exact steps you took ?

You also realize that article looks to be for the beaglebone white too right ? But it sounds as though you have the device tree overlay aspect covered. So hopefully good to go.

How you power the BBB should be irrelevant as long as you do not over do things. That is to say USB 2.0 max power supply is 500ma, and everything powered up on the BBB can use up to 472ma ( from memory ). If the only thing you’re doing aside from powering the BBB, and using the UART I do not think there should be any problems.


Thanks you for responding.

" Need more information. What is your exact problem ? "
I’m not getting any data back from the from the arduino while its plugged up to the UART ports. I tried using UART2 and 4 but can’t get anything back. Both my arduino and the BBB set for the baud rate of 9600.

"What are the exact steps you took ? "
I have a arduino device that I normally use FTDI to communicate with. Using the device tree solution, I created a new device tree and changed the mode of ports 21 & 22 to mode0. Then, plugged up the power to the 3.3v of the BBB and the rx/tx (opposite on the BB end)…but no data.
…again, thanks for responding.

Also, just retried the example with pins 11 & 13, with the device powered by the 3.3v of the BBB…still no dice.


group: pinctrl_uart5_pins
pin 28 (44e10870)
pin 29 (44e10874)

Plugged the power to what 3v3 power of the BBB ? I hope you do not mean you hooked the UART of the Arduino to the BBB UART without a logic level converter between the two. I this is the case then there is a chance you’ve burned out the UART on the BBB that you’ve hooked to. The Arduino uses 5v serial where the BBB uses 3v3 serial.

Are you using an oscilloscope or a logic Analyzer to check that there is actually UART communications happening ?

I’m a total electronic newbie that is gathering experience while tinkering. If the UART is burned on this node, then so but it, far from the end of the world. I would still like to know how to go about getting my goal accomplished. Also, I do not have an oscilloscope or logic Analyzer, but if this is the suggested hardware to get this done, then I’ll get my hands on one (one way or another). William, please provide me with you suggestions on the recommended methods for getting these two to communicate. Keep in mind that I do have a logic level convert from sparkfun in my possession. Thanks for any help you can provide, it is definitely greatly appreciated.

The article looked more than capable in describing how everything should be setup. The article you pasted a link to even went so far as mentioning that you need to level shift the serial communications between the two devices, and provided an easy to read diagram of how he/she did so.

As far as being “newb to electronics”, I can not help you with that, and you need to spend some time learning the various aspects you need for this project. Aside from that I really can not offer much other advice.

Anyhow a logic analyzer would be your cheapest bet for checking the comms, but you could even get away without one if you can eventually get it working.